Engineering Commons^™

The Effects Of Elasticity In The Foundation On The Flutter Of A Metallic High Aspect Ratio Wing, Horacio Esteban Sepic Kriskovich

Master's Theses - Daytona Beach

The goal of this thesis is to study the flutter characteristics of a metallic high-aspect ratio wing, with linearly varying chord across the semis-span, and a simulated elastic foundation. The general planform of the wing is similar to the one found in a High- Altitude Long-Endurance Uninhabited Aerial Surveillance Vehicle (HALE USAV).

The problem is studied using a simplified aerodynamic loading based on thin-airfoil theory, which is then combined with a Lagrangian formulation to solve the system as stationary. The wing has no control surfaces or external stores, and is modeled as a uniform beam with known mechanical properties, being …

Resilient Moduli Of Typical Missouri Soils And Unbound Granular Base Materials, David Newton Richardson, Thomas M. Petry, Yu-Ning Louis Ge, Y. P. Han, S. M. Lusher

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The objective of this project is to accurately determine the resilient moduli for common Missouri subgrade soils and unbound granular base materials in accordance with the AASHTO T 307 test method. The test results included moduli data from 27 common subgrade soils out of the 99 Missouri soil associations and from 5 unbound granular bases. These materials were tested at their optimum water content and at an elevated water content, which would normally occur as a worse case scenario during the life of a pavement. The five unbound granular base materials were tested at two different gradations (high and low …

Effects Of Cyclic Strain And Growth Factors On Vascular Smooth Muscle Cell Responses, Kytai Truong Nguyen, Hao Xu

Bioengineering Faculty Publications - Archive

Under physiological and pathological conditions, vascular smooth muscle cells (SMC) are exposed to different biochemical factors and biomechanical forces. Previous studies pertaining to SMC responses have not investigated the effects of both factors on SMCs. Thus, in our research we investigated the combined effects of growth factors like bFGF (basic fibroblast growth factor), TGF-�� (transforming growth factor ��) and PDGF (platelet-derived growth factor) along with physiological cyclic strain on SMC responses. Physiological cyclic strain (10% strain) significantly reduced SMC proliferation compared to static controls while addition of growth factors bFGF, TGF-�� or PDGF-AB had a positive influence on SMC growth …

Topology Optimization Using Hyper Radial Basis Function Network, Aditya P. Apte

Mechanical and Aerospace Engineering Dissertations - Archive

Topology optimization has been conventionally used in automobile and aerospace industries to produce lightweight structures for minimum compliance or maximum fundamental frequency. Today, topology optimization finds application in solving diverse types of problems ranging from medicine to consumer products. Popular continuum based method SIMP fails to provide global solution due to too many variables involved. In this work, a novel hyper radial basis function network is presented as topology description function. The proposed approach provides drastic reduction in number of design variables involved in topology optimization. This makes the use of heuristic global solution possible. Parallel processing, reanalysis formulation and …

Optimal-Control Theoretic Methods For Optimization And Regulation Of Distributed Parameter Systems, Jennifer Dawn Goss

Mechanical and Aerospace Engineering Dissertations - Archive

Optimal control and optimization of distributed parameter systems are discussed in the context of a common control framework. The adjoint method of optimization and the traditional linear quadratic regulator implementation of optimal control both employ adjoint or costate variables in the determination of control variable progression. As well both theories benefit from a reduced order model approximation in their execution. This research aims to draw clear parallels between optimization and optimal control utilizing these similarities. Several applications are presented showing the use of adjoint/costate variables and reduced order models in optimization and optimal control problems. The adjoint method for shape …

Transient Flow Analysis Of Filling In Pulse Detonation Engine, Veera Venkata Suneel Jinnala

Mechanical and Aerospace Engineering Theses - Archive

The Pulse Detonation Engine (PDE) is considered to be a propulsion system of future air vehicles. The objective of the present study is to model an efficient inlet system for filling the detonation tube completely with the fuel/air mixture. In the present study the filling processes is modeled numerically using CFD code FLUENTTM. Calculations for the gas flow are carried out by solving the Navier-Stokes equations coupled with the k- ? turbulence model. Five different inlet configurations were proposed and simulated in both two-dimensionally and three-dimensionally. The model with an orifice plate at the inlets ensured the desired optimum results. …

Guidance Of Receiver Aircraft To Rendezvous With Tanker In The Presence Of Wind, Jane-Wit Kampoon

Mechanical and Aerospace Engineering Theses - Archive

This thesis work addresses the problem of aircraft rendezvous in the presence of prevailing wind for automated aerial refueling operations. A modified point-parallel rendezvous procedure is defined. The tanker aircraft performs a racetrack maneuver along a pre-specified refueling orbit. The receiver aircraft enters the refueling area through a fixed point and flies along the refueling line that is aligned with on of the straight legs of the race track. It is the responsibility to meet the tanker at the rendezvous point. A virtual target is used to define the trajectory of the refueling orbit. A nonlinear guidance algorithm is used …

Experimental Investigation Of Flow Boiling And Spray Cooling On Enhanced Surfaces In Fc-72, Gilberto Morenp

Mechanical and Aerospace Engineering Dissertations - Archive

In this study the effect of a recently developed, thermally conductive microporous coating on flow boiling and spray cooling performance was studied using FC-72 as the working fluid. The overall goal is to further increase heat transfer in forced convection systems and in doing so, provide a viable option for future cooling applications. In flow boiling, the coating increased heat transfer coefficients by as much as 400% and produced values exceeding 40,000 W-m-2 K-1. This enhancement is believed to be a result of both an increase in active nucleation sites and a decrease of the superheated liquid layer. It is …

A Comprehensive Study Of Recycled Concrete Aggregates As A Drainable Base Layer For Pavements, Juan Bosquez

Civil Engineering Dissertations - Archive

The use of recycled materials in construction is becoming increasingly popular due to the shortage of raw materials. Coupled with the environmental concerns surrounding the quarrying of natural minerals, waste materials are being considered as viable replacement sources. By recycling waste materials, available landfill space is increased and costs of transportation are reduced. This dissertation study was conducted to evaluate the use of recycled concrete aggregates as flexible base as per the requirements of the Texas Department of Transportation (2004). Two sources of recycled aggregates and one source of natural limestone aggregate were collected from the Dallas/Fort Worth Area and …

Reliability Of Advanced Dielectrics In Gate Oxide And Device Level Packaging In Mems, Mohammad Shahriar Rahman

Electrical Engineering Dissertations - Archive

The focus of this work is to study the feasibility, reliability and applicability of advanced dielectrics in both Metal Oxide Semiconductor Field Effect Transistor (MOSFET) gate oxide and device level packaging for Microelectromechanical Systems (MEMS). The scaling of silicon based MOSFET is approaching physical limits imposed by atomic structure. This continuous scaling trend of complementary MOSFET technologies introduces new challenges relating to power, heat and device behavior. To overcome the power dissipation and heating problems arising from gate leakage, high dielectric constant (high-k) materials are proposed. Hafnium based high-k dielectric layers and metal gate electrodes have been extensively investigated as …

Optimization Of Hydrogen Filling Station, Weiping Xiao

Electrical Engineering Theses - Archive

Due to the price hike of the fossil fuel and the concern of the global warming, the hydrogen economy can be envisioned to address those problems. After the Energy Bill was announced in 2005, a transition of national energy system from hydrocarbon to hydrogen had been recognized. However, safe and convenient refueling and widespread availability of hydrogen from various energy sources are the prerequisite for the development of hydrogen economy. This research focuses on the hydrogen filling station with on-site hydrogen production by electrolysis of water. The virtual wind farm and on-site installed photovoltaic (PV) supply the main and renewable …

Battery Identification Methods Based On Equivalent Circuit Model, Matthew Cole Ragsdale

Electrical Engineering Theses - Archive

Development of an intelligent battery diagnostic system is a necessity for future transportation industry. These technologies will have the potential to create profound impact in other industries such as portable electronics. This thesis reports on battery identification methods that are primarily engineered to detect the chemistry, number of cells, and state of charge in an unknown package of batteries. The proposed methods have the potential to be used for condition monitoring in a known set of batteries thereby, creating a health monitoring apparatus that can be an integral part of a battery management system using any of the prominent lead …

Blocking Reader: Design And Implementation Of A Low-Cost Passive Uhf Rfid Blocking Reader, Gaurov Narayanaswamy

Electrical Engineering Theses - Archive

In this thesis I present a low-cost passive UHF ISO 18000-6C RadioFrequency Identification, or RFID, reader that is feasible for mobileand privacy applications. Low cost readers are necessary to achievethe promised cost savings and enhanced revenue generation that theInternet of Things promises to deliver. Low cost readers may beinstalled virtually everywhere, providing real-time asset monitoringand a host of new and innovative applications yet to be conceived.While pervasively deployed readers provide tremendous benefits, thepromiscuous nature of the 18000-6C tags means that the readers alsopose a threat to personal security and privacy. Privately owned tags on a person will be read by …

Dlp Hyperspectral Imaging For Surgical And Clinical Utility, Robert Paul Francis

Bioengineering Theses - Archive

Surgeons want technology to help them see differences in tissue chemistry. If they know how oxygenated tissues and organs are during medical procedures, they are more able to eliminate dangerous tissues and maintain viable organs. Hyperspectral imaging non-invasively measures the optical absorbance spectrum of each pixel in a spatial field of view and, with chemometric image processing, can visualize the spatial distribution of tissue oxygenation. Current hyperspectral imaging systems are too slow to monitor real-time physiological changes in live tissue. Therefore, a novel DLP Hyperspectral Imaging (DLP HSI) system is developed for real-time, non-invasive, in-vivo imaging of tissue chemistry in …

A Novel Device For The Establishment Of An Animal Model Mimicking Spinal Deformity Surgery For Neurological Deficit Risk Mitigation, Bradley Elmer

Bioengineering Theses - Archive

Correction forces during spine deformity surgery impart significant multidirectional stress forces to the spinal cord, which in some cases result in severe damage to the spinal cord and permanent paralysis, the most feared complication. Animal models are critical for the development of neuroprotective strategies. However, those currently available are limited to contusion, transection, or unidirectional distraction injuries, which fail to replicate the multidirectional forces that occur during spine corrective surgery. In order to develop an improved model of distraction spinal cord injury we designed a device based on intervertebral grip fixation and linear actuators, capable of inducing controllable bidirectional distraction …

In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery, Dipendra Raj Gyawali

Bioengineering Theses - Archive

In situ crosslinkable elastic materials are increasingly being explored for various biomedical applications such as drug delivery and tissue engineering due to their site specific nature. The creation of an in situ crosslinkable elastomer rich in pendant chemistry has been a challenge in the field of biomaterials. Herein, we have developed two new in situ biodegradable materials: poly(octamethylene maleate citrates) (POMC) and poly(poly(ethylene glycol) maleate citrate) (PPEGMC). These materials are all low molecular weight in their pre-polymeric form, which shows their potential to be used as an injectable biomaterial. The preservation of pendant carboxylic and hydroxyl groups in these polymeric …

Development Of An Optical Spectroscopic Method To Detect Neurohemodynamic Changes Induced By Pain In Rats, Sweta Narvenkar

Bioengineering Theses - Archive

In my optical spectroscopy study, multi-channel, thin optical probes with short source-detector separation have been implemented, calibrated, and used along with a multi-channel spectrometer as a quantitative technique to observe changes in vascular hemoglobin concentration and hemoglobin oxygen saturation as well as light scattering of tissues. Each of the four needle probes used in my study consists of two bifurcated fibers; one fiber is connected to a halogen light source and the other fiber to a CCD-array spectrometer having a spectral window from 450 nm to 900 nm. Each fiber is 100 micron in diameter. As we utilized the four …

Integration Of Data Mining Algorithms And Control Charts For Multivariate And Autocorrelated Processes, Weerawat Jitpitaklert

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

The objective of this dissertation is to integrate state-of-the-art data mining algorithms with statistical process control (SPC) tools to achieve efficient monitoring in multivariate and autocorrelated process. Process monitoring and diagnosis have been widely recognized as important and critical tools in system monitoring for detection of abnormal behavior and quality improvement. Although traditional SPC tools are effective in simple manufacturing processes that generate a small volume of independent data, these tools are not capable of handling the large streams of multivariate and autocorrelated data found in modern manufacturing/service systems. As the limitations of SPC methodology become increasingly obvious in the …

Production And Storage Of Hydrogen, Michael Muller

Masters

The Faculty of Electrical Engineering and Information Technology at the University of Applied Science in Darmstadt runs several hydrogen-related experiments at their fuel cell laboratory. In cooperation with the Technological University Dublin (DIT), a new project was started in 2007. The aim of this project was to develop an energy storage system, which would work with hydrogen as a high quality energy storage. This system was developed for using the electricity of solar panels in order to run an electrolyser. Hydrogen is produced and afterwards stored in an adequate storage tank. Once the hydrogen has been stored, it can be …

Nonlinear Dynamic Analysis Of Hybrid Frames, Dobrinka Radulova

Civil Engineering Theses - Archive

This study proposes a hybrid frame system consisting of rigid and semi-rigid connections subjected to a dynamic loading. Two building geometries are chosen to represent low-rise and high-rise buildings. Multiple locations for placement of semi-rigid connections are proposed, and the hybrid systems with the most efficient energy dissipation are identified. During this analysis, five earthquake records are used to provide a spectrum of frequencies. Five practical semi-rigid connection types and one connection with analytical parameters are also modeled into the selected hybrid combinations by applying zero-length springs at the ends of beams, in which their nonlinear constitutive relation is defined …

Rating Requirements Of The Upqc To Integrate The Fsig Type Wind Generation To The Grid, N. Jayanti, Malabika Basu, Michael Conlon, Kevin Gaughan

Articles

The ability of wind generation to remain connected to the grid in the event of system faults and dynamic reactive power compensation are two aspects of grid integration, which have received particular attention. The wind driven, fixed-speed induction generator (FSIG) on its own fails to fulfil these requirements of grid integration. The application of a unified power quality conditioner (UPQC) to overcome the grid integration problems of the FSIG is investigated. The role of the UPQC in enhancing the fault ride-through capability of the generator is also investigated under both full and partial terminal voltage restoration. A realistic estimation of …

Structural Analysis And Active Vibration Control Of Tetraform Space Frame For Use In Micro-Scale Machining, Kevin Knipe

Electronic Theses and Dissertations

This research thesis aims to achieve the structural analysis and active vibration damping of the Tetraform machining structure. The Tetraform is a space frame made up of four equilateral triangles with spherical masses at the four vertices. This frame was originally developed for grinding of optical lenses and is now being adapted for use in micro-precision milling. The Tetraform is beneficial to the milling process due to its exceptionally high dynamic stiffness characteristics, which increases the machining stability and allows for higher material removal rates and accuracy. However, there are still some modes of vibration that are critical to the …

Tertiary Creep Damage Modeling Of A Transversely Isotropic Ni-Based Superalloy, Calvin Stewart

Electronic Theses and Dissertations

Anisotropic tertiary creep damage formulations have become an increasingly important prediction technique for high temperature components due to drives in the gas turbine industry for increased combustion chamber exit pressures, temperature, and the use of anisotropic materials such as metal matrix composites and directionally-solidified (DS) Ni-base superalloys. Typically, isotropic creep damage formulations are implemented for simple cases involving a uniaxial state of stress; however, these formulations can be further developed for multiaxial states of stress where materials are found to exhibit induced anisotropy. In addition, anisotropic materials necessitate a fully-developed creep strain tensor. This thesis describes the development of a …

New Heuristics For The 0-1 Multi-Dimensional Knapsack Problems, Haluk Akin

Electronic Theses and Dissertations

This dissertation introduces new heuristic methods for the 0-1 multi-dimensional knapsack problem (0-1 MKP). 0-1 MKP can be informally stated as the problem of packing items into a knapsack while staying within the limits of different constraints (dimensions). Each item has a profit level assigned to it. They can be, for instance, the maximum weight that can be carried, the maximum available volume, or the maximum amount that can be afforded for the items. One main assumption is that we have only one item of each type, hence the problem is binary (0-1). The single dimensional version of the 0-1 …

Alliances In Graphs: Parameterized Algorithms And On Partitioning Series-Parallel Graphs, Rosa Enciso

Electronic Theses and Dissertations

Alliances are used to denote agreements between members of a group with similar interests. Alliances can occur between nations, biological sequences, business cartels, and other entities. The notion of alliances in graphs was first introduced by Kristiansen, Hedetniemi, and Hedetniemi in . A defensive alliance in a graph G = (V, E) is a non empty set S ⊆ V where, for all x ∈ S, |N[x] ∩ S| ≥ |N[x] − S|. Consequently, every vertex that is a member of a defensive alliance has at least as many vertices defending it as there are vertices attacking it. Alliances can …

On The Application Of Locality To Network Intrusion Detection: Working-Set Analysis Of Real And Synthetic Network Server Traffic, Robert Lee

Electronic Theses and Dissertations

Keeping computer networks safe from attack requires ever-increasing vigilance. Our work on applying locality to network intrusion detection is presented in this dissertation. Network servers that allow connections from both the internal network and the Internet are vulnerable to attack from all sides. Analysis of the behavior of incoming connections for properties of locality can be used to create a normal profile for such network servers. Intrusions can then be detected due to their abnormal behavior. Data was collected from a typical network server both under normal conditions and under specific attacks. Experiments show that connections to the server do …

Adaptive Efficiency Optimization For Digitally Controlled Dc-Dc Converters, Wisam Al-Hoor

Electronic Theses and Dissertations

The design optimization of DC-DC converters requires the optimum selection of several parameters to achieve improved efficiency and performance. Some of these parameters are load dependent, line dependent, components dependent, and/or temperature dependent. Designing such parameters for a specific load, input and output, components, and temperature may improve single design point efficiency but will not result in maximum efficiency at different conditions, and will not guarantee improvement at that design point because of the components, temperature, and operating point variations. The ability of digital controllers to perform sophisticated algorithms makes it easy to apply adaptive control, where system parameters can …

Investigation Of Damage Detection Methodologies For Structural Health Monitoring, Mustafa Gul

Electronic Theses and Dissertations

Structural Health Monitoring (SHM) is employed to track and evaluate damage and deterioration during regular operation as well as after extreme events for aerospace, mechanical and civil structures. A complete SHM system incorporates performance metrics, sensing, signal processing, data analysis, transmission and management for decision-making purposes. Damage detection in the context of SHM can be successful by employing a collection of robust and practical damage detection methodologies that can be used to identify, locate and quantify damage or, in general terms, changes in observable behavior. In this study, different damage detection methods are investigated for global condition assessment of structures. …

Direct Manipulation Of Virtual Objects, Long Nguyen

Electronic Theses and Dissertations

Interacting with a Virtual Environment (VE) generally requires the user to correctly perceive the relative position and orientation of virtual objects. For applications requiring interaction in personal space, the user may also need to accurately judge the position of the virtual object relative to that of a real object, for example, a virtual button and the user's real hand. This is difficult since VEs generally only provide a subset of the cues experienced in the real world. Complicating matters further, VEs presented by currently available visual displays may be inaccurate or distorted due to technological limitations. Fundamental physiological and psychological …

Search And Delivery Techniques In Peer-To-Peer Networks, Tai Do

Electronic Theses and Dissertations

The presence of millions of interconnected personal computing devices has given rise to a new class of decentralized networking applications, which are loosely labeled as peer-to-peer (P2P) applications. These P2P applications leverage resources such as processing cycles, storage, content, and network bandwidth available to the user devices, which are also known as peers. A number of current systems - SETI@home, Napster, BitTorrent, and Pastry - are examples of these emerging P2P systems. To fully realize the potential of the peer-to-peer technology, there is a need to define and provide a set of core competencies, serving as the basic services upon …